The present invention relates to a device for selective flow connection of exhaust piping of cutting tools to an exhaust fan, comprising a distributor connected on one side to the exhaust fan and on the other side to the exhaust piping and comprising a switching device for closing and opening the exhaust piping connected to the distributor.
Cutting tools are provided with exhaust piping, which must be attached to an exhaust fan for eliminating the accumulating cuttings, for extracting the accumulated cutting waste which builds up with cutting tools. If a fan is provided the exhaust piping of the individual tools is to be connected alternately to the exhaust fan during use. This can occur in laborious fashion in that the respective exhaust piping is connected to the exhaust fan after the unrequired exhaust piping is extracted. Easier handling results from connecting the exhaust piping of all tools to the exhaust fan by way of a distributor, though in this case the distributor connections of the exhaust piping must be fitted with a switching device for opening and closing the connections; not only is this associated with considerable structural expense, but also enables fault circuits so that there is the danger that the required suction effect for extracting the accumulating cuttings of the machinery currently being operated is not available.
Similar disadvantages emerge in another known construction (DE 89 05 017 U1), wherein the connections for the exhaust piping of the cutting machinery are provided in the side walls of a rectangular housing which accommodates a flap for all connections operable by means of a separate servomotor. Because all connections of the housing are connected by way of a separate connector to the common exhaust fan, there is considerable structural expense which, according to the number of connections opened by the flaps, attracts different suction effects for the connected exhaust piping.
The object of the invention is to design a device for selective flow connection of exhaust piping of cutting machinery to an exhaust fan of the type initially described, such that switching errors are excluded by means of simple structural means.
The invention solves this problem, whereby the distributor forms a pot-shaped housing for the switching device, whose floor bears the connection for the exhaust fan and whose peripheral wall bears the connections for the exhaust piping, the switching device presents a pot-shaped housing insert which is connected to the housing floor with its peripheral wall enclosing the connection for the exhaust fan and seals off the housing with its floor in the manner of a cover, and whereby a passageway aligning in individual adjustable settings with a connection for the exhaust piping is provided in the peripheral wall of the rotatably adjustable housing insert closing off the connections for the exhaust piping.
As a consequence of these measures the housing insert of the switching device connects the connection of the exhaust fan in each of its adjustable positions by means of the passageway in the peripheral wall with only one of the connections for the exhaust piping, effectively excluding any defective flow connections between the exhaust fan and several tools. Despite this forced control very simple structural ratios result because the pot-shaped housing insert closes off the similarly pot-shaped housing in the manner of a cover and tightly and adequately seals off the connection for the exhaust fan in the floor of the pot-shaped housing with the free end of the peripheral wall. In this respect it must be considered that as a result of the subpressure prevalent in the pot-shaped housing the housing insert is drawn into the housing top. No special sealing seat is thus required to ensure adequate tightness between the housing insert and the housing. In the case of greater demands on tightness sealing inserts are sufficient, for example in the form of felt inserts or similar. The pot-shaped housing can turn out to be relatively small, because provision has to be made for the connections of the exhaust piping only along the peripheral wall of the housing.
Particularly simple connection conditions are prevalent when the pot-shaped housing presents the form of a regular prism. In this case a uniform connection surface is available for each connection of the exhaust piping. If the exhaust piping has an identical diameter, the side surfaces of the prism may have a square shape matching the diameter of the exhaust piping. In the event of differing diameters of the exhaust piping the side surfaces of the prism are to naturally fit the largest connection diameter. Such a prismatic housing shape allows a modular housing structure made up of separate connection plates which are to be connected to a floor in the shape of a regular rectangle. The housing insert of the switching device can, according to the prismatic shape of the housing, also be prismatic in design, such that the different adjustable positions, in which the housing insert can be interlocked in the housing, can result from the prismatic shape. For the housing insert to be rotated it must be withdrawn from the housing before it can be reset axially into the housing after a corresponding rotatable adjustment.
If importance is attached to a rotary bearing of the housing insert to its rotatable adjustment, the housing of the switching device can present a cylindrical form and be set into a cylindrical housing. But it is also feasible to utilize the advantages of a prismatic housing in conjunction with a cylindrical housing insert if the prismatic housing takes up a corresponding bearing cartridge for the rotatable bearing of the housing insert. In such a case, in the interests of ensuring a sufficiently tight connection of the connections for the exhaust piping in the peripheral wall of the prismatic housing on the one hand, and cylindrical housing insert on the other, the bearing cartridge for the prismatic housing may present radial partitions between the side edges of the prismatic housing and the peripheral wall of the cylindrical housing insert. Connecting chambers separated from one another inside the housing are formed by these partitions located between the housing insert and the individual connections of the exhaust piping.
Because the respective rotatable adjustment of the housing insert of the switching device determines the connection of one of the intake pipes to the exhaust fan, the respective flow connection can be established easily by the housing insert presenting an actuating handle pointing in the direction of the passageway and located on the outside of the floor.
If machinery is used requiring extraction of cuttings on both sides the exhaust fan is to be connected with two exhaust pipes belonging to this machinery. This can be considered in a housing insert swivel-mounted in the housing by interposition of the housing insert, whereby the passageway in the peripheral wall of the housing insert frees up the flow path to two adjoining connections in the peripheral wall of the housing. Such interposition is, however, not possible in prismatic housing inserts. For intake pipes to be connected to the exhaust fan in pairs in this embodiment the peripheral wall of the prismatic housing insert can present another sealable passageway with an optionally openable cover on an additional side surface so that this additional passageway can be freed up as required.